7 January 1948, Captain Thomas F. Mantell, a Kentucky Air National Guard pilot, died in the crash of his P-51 Mustang fighter plane near Franklin, Kentucky, United States, after being sent in pursuit of an unidentified flying object. While following the object, he climbed beyond 25,000 feet (7,600 m) and blacked out from a lack of oxygen. The military later identified the craft he was pursuing as likely a Skyhook weather balloon
S 34° 05.782′ E 139° 00.159′